This is not really pixel art, so should probably be moved to low res. Leaving that alone, I have an issue with all the blurring going on I think, I feel everything needs to be crisper. The individual drawings are quite good, but I feel that animated they don't work for two reasons:
1) Framerate is too low for something this big, it's just too choppy
2) There's no sense of squash/stretch (classic animation term), everything shrinks/grows without much reason to it. You should try to imagine how forms deform over time and try to get a sense of movement going. The simpler sidekick ball does a nice squash/stretch over time, so I'm sure you're familiar with the technique.